The invention relates to a method of manufacturing a semiconductor device with a rectifying Schottky junction, comprising a semiconductor body with a semiconductor substrate, by which method a stack is formed in the semiconductor body of a first semiconductor region of a first conductivity type formed by means of epitaxy and a second semiconductor region having a small thickness and a high doping concentration, and by which method a metal layer is provided on the semiconductor body at the area of the second semiconductor region so as to form the Schottky junction with the semiconductor body, and the thickness and doping concentration of the second semiconductor region are chosen such that the height of the Schottky barrier of the Schottky junction is influenced, while a third semiconductor region of a second conductivity type opposed to the first is provided from the surface of the semiconductor body into the first semiconductor region at at least two mutually opposed sides of the second semiconductor region.
Such a method is used for giving a Schottky barrier, wherever this is used, a current-voltage characteristic, especially in the forward direction, which is most suitable for the application. The use of a thin, strongly doped barrier layer renders possible a greater variation in said characteristic than is possible, for example, through the choice of different Schottky metals.
Such a method is known from U.S. Pat. No. 4,089,020. It is described therein (see FIG. 4) how a first n-type semiconductor region is formed as an epitaxial layer on an n-type silicon semiconductor substrate. In the semiconductor region thus formed, a thin, strongly doped second semiconductor region of p-type silicon is formed by means of implantation, acting as a layer which influences the barrier for a Schottky junction to be formed. This junction is provided with an annular third semiconductor region which embraces the second semiconductor region at at least two mutually opposed sides, entirely surrounding it in this case, which third region is formed from the surface of the semiconductor body through the local diffusion into it of p-type impurities and is provided with a doping concentration and a geometry such that leakage currents and breakdown at the edge of the Schottky junction to be formed are limited and prevented, respectively, acting as a so-called guard ring. A metal layer of aluminum, which forms a Schottky junction with the semiconductor body, is provided on the surface of the semiconductor body and in contact with the second semiconductor region. The substrate is provided with an ohmic contact.
A disadvantage of this method is that the properties of the devices obtained thereby, in particular the current-voltage characteristic, are not satisfactorily controllable and in addition not well reproducible. The known method is less suitable for mass manufacture on account of this.